CmlI is an N-oxygenase in the biosynthesis of chloramphenicol

Haige Lu, Emmanuel Chanco, Huimin Zhao

Research output: Contribution to journalArticlepeer-review


The N-oxygenation of an amine group is one of the steps in the biosynthesis of the antibiotic chloramphenicol. The non-heme di-iron enzyme CmlI was identified as the enzyme catalyzing this reaction through bioinformatics studies and reconstitution of enzymatic activity. In vitro reconstitution was achieved using phenazine methosulfate and NADH as electron mediators, while in vivo activity was demonstrated in Escherichia coli using two substrates. Kinetic analysis showed a biphasic behavior of the enzyme. Oxidized hydroxylamine and nitroso compounds in the reaction were detected both in vitro and in vivo based on LC-MS. The active site metal was confirmed to be iron based on a ferrozine assay. These findings provide new insights into the biosynthesis of chloramphenicol and could lead to further development of CmlI as a useful biocatalyst.

Original languageEnglish (US)
Pages (from-to)7651-7654
Number of pages4
Issue number37
StatePublished - Sep 16 2012


  • Arylamine oxygenation
  • Chloramphenicol biosynthesis
  • Di-iron oxygenase
  • N-Oxygenation

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Drug Discovery


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